Materials such as animal feeds, feedstuffs, and pharmaceutical and cosmetic compositions contain a variety of components. In the animal feed industry, for example, an animal feed may contain protein, amino acids, vitamins and minerals, among other things. In the pharmaceutical and cosmetic industries, compositions can contain one or more active ingredients together with various excipients and additives. Control and monitoring of the composition of such materials has a number of advantages. For example, proper control over the nutrient composition of animal feeds assists in the healthy and efficient growth of the animals. Likewise, monitoring the composition of pharmaceutical or cosmetic compositions over time, for instance during storage, assists in evaluating the stability of the materials.
At least in the animal feed industry, raw materials for use in feeds can vary significantly in composition. In fact, the content level of any given component in a material typically varies within certain tolerance limits about an average value among different samples of the material. Those variations render it difficult to include all desired levels of components in an animal's diet. One attempt at ensuring those desired levels includes assessing the natural variation of component levels in a material, and adding supplemental components to all batches of the material to achieve a guaranteed high level of the component. This technique does not reduce the natural variation in the component levels. Instead, it simply raises the average level of the component to a higher average level. Thus, some batches of the raw material will still contain less than needed levels of components. Other batches, on the other hand, will contain excess levels of component. In the case of excess nutrient in an animal feed, for example, that can lead to extra cost and higher levels of pollution in the form of nitrogen and phosphorus in the manure of animals fed those diets.
Another attempt at ensuring desired levels of components in animal feed involves measuring the levels of the component in batches of material, and either supplementing that level where necessary with additional components or directing the material into an application that can favorably use the material as it is. Success in such a process depends in large part on the accuracy and ease of the measurement of the component levels. The most favorable measurement is both accurate and fast. That applies as well to measurements in other industries, for example the pharmaceutical and cosmetic industries.
One method of determining the content levels of components in materials is by physical examination or testing and quantification of the components of interest. In the field of feedstuffs, those techniques are referred to as “wet chemistry” or in vitro determinations. In vitro techniques may also determine compositions of pharmaceutical or cosmetic materials. Although accurate in determining certain component levels in materials, these techniques are time consuming.
Another method for measuring the content levels of components in materials involves predicting those levels based on the near infrared reflectance spectrum (“NIRS”) of the materials. A material subjected to near infrared radiation will emit a response to the radiation, which may be plotted in the form of a spectrum. A regression technique may correlate a given response spectrum of a material to reference data such as a known content levels of a component in the material. The content level of the component in a new sample of material may then be predicted by obtaining the near infrared spectrum of the material and applying the relevant correlation.
Regression techniques like that described above can be used, for example, by a feed mill, to predict the protein, amino acid, moisture, fat, and ash contents of feedstuffs, as discussed in Van Kempen and Simmins, “Near-infrared Reflectance Spectroscopy in Precision Feed Formulation,” J. Appl. Poultry Res., vol. 6, pp 471-475 (1997) and Van Kempen and Jackson, “NIRS May Provide Rapid Evaluation of Amino Acids,” Feedstuffs (Dec. 2, 1996). Co-pending U.S. patent application Ser. No. 09/471,420, filed on Dec. 23, 1999, also discusses a method of predicting the content level of vitamins in materials using a regression technique. The contents of the three above-cited documents are expressly incorporated herein by reference in their entireties. These techniques require an initial investment by the user to establish the appropriate database calibration between near infrared spectra of the materials and the content levels of components in the materials.
A service for amino acid predictions in raw materials using NIRS is discussed in AminoNews, vol. 1, no. 3, pp. 11-14 (December 2000), the contents of which are expressly incorporated herein by reference in its entirety. This service is described as requiring a period of a few days for analysis of the material of interest. That delay can include time for shipping samples of material to the service provider for analysis. Use of this service also involves an economic cost for shipping the materials, as well as possible delay and extra documentation for shipping materials through customs when mailing internationally. The calibration sets for this service are disclosed as generated using wet chemistry analysis correlated with near infrared spectra of the materials.